Study On Theg Green Synthesis Process Of Cresidine

Section 1:The green synthesis of cresidineThe paper begins with p-cresol as the starting material.2-nitro-p-cresol is synthesized through the nitration reaction in the presence of dilute nitric acid,and then 4-methyl-2-nitro-anisole is formed after the phenolic hydroxyl group of 2-nitro-p-cresol is methylated by the methylating reagent,for example,methyl chloride.And 4-methyl-2-nitro-anisole is reduced directly to the target product,cresidine,by hydrogenating them in the presence of a hydrogenation catalyst,for instance,Raney nickel.After the three step reaction,the product yield was 72.68%,and the purity of final product was 98.45%by GC external standard method.After the recovery of raw materials used intermediates,the total yield of the product can reach 80.16%.The advantage of the preparation process is as follows.It adopts the less toxic methylation reagent,methyl chloride,instead of highly toxic dimethyl sulfate and the friendly hydrogenation method so that it makes the total synthesis process more secure and more suitable for the requirements of green manufacture.In the mean-while,the paper is to research the recycle use of raw materials,intermediate and catalyst,etc.it further reduces the cost of production and improve the atom utilization.Therefore,it is a new chemical synthesis route,which conforms to the green chemistry idea.Section2:the recovery of triphenylphosphine from triphenylphosphine oxideIn addition,another work of-this paper is to take triphenylphosphine oxide.a by-product of phosphorus yilide reaction,as the starting material.triphenvl-phosphine oxide is chlorinated to triphenylphosphine dichloride by chlorination reagents such as oxalyl chloride,triphosgene,and then hrough the aluminum powder,triphenylphosphine is recovered with the catalytic reduction.The conversion rate of the product was 64.36%and the yield was 49.18%.The purity of the product was 99.81%by LC external standard method.Or by another means,triphenylphosphine is obtained by hydrogenation reduction.The conversion of the product was 82.39%,the yield was 62.47%,and the product purity was 99.72%.In this work,hydrogenation reduction is a more economical,reasonable and environmentally friendly route for the reduction of triphenylphosphine oxide,the by-product of triphenylphosphine.which reduces the cost of production.